This invention relates generally to a method and apparatus for microfiche tabbing, and more specifically to more accurately aligning the image grids of the fiche with the identification tab.
Many microfiche storage and retrieval units, such as those manufactured by Tera operate similar to photographic slide storage and retrieval units. Each fiche is stored at a separate location in a carousel. To select a particular fiche, the carousel is rotated until the fiche to be selected is in front of a removal device-- usually a mechanism which attaches to the tab and lifts the fiche away from the carousel.
Placing a tab on the edge of microfiche serves two main purposes: to provide a means for identifying each fiche in a group and distinguishing it from the others, and providing a rigid edge for the removal mechanism to attach. The tab, which is metallic, contains a pattern of cut-outs on its outer edge that represents a unique binary number. To select the desired fiche, a narrow surface, which is parallel to the identifying tabs, is magnetized according to the pattern of the identifying notches on the fiche. Only one microfiche in the group will match the magnetic pattern.
When the fiche is found the carousel stops to allow the removal mechanism to remove the desired fiche.
During the preparation of the fiche, it is placed in a tabbing press, and the tab is aligned with the edge of the fiche. Afterwards the fiche is usually placed on a registration block to assure that the edge of the tab is parallel to the image grids. Nonalignment generally results in loss of portions of images during viewing. In the case of nonalignment the fiche must sometimes be re-tabbed (if possible) or even dispensed with.
The prior art method of tabbing and registration usually does not discover misalignment until after the identifying tab is attached, which often results in a waste of time and materials. Additionally, the distance varies from fiche to fiche, and the grids are not always parallel to the edge of the fiche.